The present invention is directed to devices and methods for concentrating fluids. More particularly, the present invention is directed to devices and methods for concentrating autologous biological or body fluids.
Concentration and/or filtration of body fluids have long been practiced in the medical arts. Many medical treatments involve applying a fluid or gel-like substance to a wound or disease location. For some medical treatments, the fluid or gel-like substance is obtained from a body fluid of another person or animal. Body fluids, components of body fluids, or components of other body parts, such as tissue, may also be obtained from other species and used on human patients. Examples of such biological materials which are commonly used in current medical applications on humans are components of mammalian blood and bone, such as allogenic, xenogenic or autogenic graft materials, including from human, bovine and porcine sources. In some applications, the filtration and/or concentration process is carried out in an ongoing, streaming process, wherein the body fluid is simultaneously removed from the patient's body and then downstream returned to the patient's body. In other applications, the filtration and/or concentration process is carried out in a batch process, wherein an amount of the body fluid is removed from the body as a unit, treated, and then returned to the patient's body as a unit.
More recently, body fluids such as blood fractions separated by centrifugation have been further filtered to increase cell or component concentrations in the filtrate. U.S. Pat. Nos. 5,733,545; 6,010,627; and 6,342,157 show examples of this, and are incorporated by reference. Such concentrated, centrifuged body fluids have been shown to be useful in various treatment modalities, such as applying the concentrated blood component directed to an orthopedic wound site. However, the methods and devices taught in the above patents have shortcomings which have prevented widespread acceptance and use in an operating environment. For example, the fluid or gel-like substance obtained from a body fluid of another person or animal is used in treatment and when applied to a patient, increases the risk for infection or diseases such as hepatitis or AIDS. The use of autologous body fluids avoids the risk of contracting a disease from external body fluids. When body fluids or components of body fluids are obtained from other species for use in human treatment, adverse reactions such as allergies, rejection, etc. can occur. The use of autologous body fluids also avoids the risk of rejection and other adverse reactions to fluids or tissue from an outside source.
Therefore, there is a need for devices and methods for concentrating and/or filtering body fluids or autologous fluids in an efficient manner that prevents contamination of the fluids and allows the fluids to be used in treatment procedures where the risk of contamination, infection, or rejection remains high.